This invention relates to hydraulic fluid control valves, and more particularly to a so-called "fluid fuse" in which the normally open in-line valve is automatically responsive to the passage of a predetermined volume of fluid by closing off the flow.
In certain hydraulic systems, hydraulic fluid is supplied under pressure to one or more hydraulic actuators. Each actuator may be supplied with an in-line control valve. Each actuator may require only a certain maximum volume of hydraulic fluid for full motion. The actuator, its control valve or the connecting lines may rupture or leak. This could cause dangerous release of hydraulic fluid and depressurizing of the entire hydraulic system. To prevent this from happening, it is desirable to be able to automatically seal off the line from the fluid pressure source. It is useful to have a safety shut off valve or hydraulic fuse which can be adjusted to shut off when a predetermined volume of fluid has passed. It should be automatically resettable so that smaller volumes can pass through repeatedly without accumulating on the metering mechanism, but should remain closed once it has been actuated until the pressure at the source has been removed to permit the device to reset.